The Virtual Pooled Registry (VPR) Project will facilitate the linkage of confidential central cancer registry databases with existing sets of patients included in cohort studies, post-marketing surveillance as well as clinical trials for the purpose of providing follow-up information on these patients who may exist within a central cancer registry?s database. The current method for these linkages requires the researcher to work directly with each registry involved in the follow-up process including preparing and completing IRB documents, working with the registry to submit a standard dataset. This often requires significant time and resources and frequently there are no matches. For a large cohort study this may involve direct contact with a large percent of the State and regional central cancer registries in the United States. The purpose of the VPR project is to create a capacity similar to the National Death Index without the creation of an aggregated national level cancer patient database. The VPR will consist of ?one stop shop? process through which an interested researcher could submit one research application and one research file which will undergo one standardized linkage simultaneously at multiple registries.